FEW SCIENTISTS can have engendered the respect and affection with which Ethelwynn Trewavas is held by colleagues throughout the world. Her unselfishness, great knowledge of matters ichthyological, and her patience, will long be mentioned whenever those studying fishes reminisce about the 'greats' in their field.
She will be remembered particularly by those who worked in isolated places far removed from libraries and study collections. No requests for help, no matter however complex or abstruse its content, went unanswered, and personal visitors to the British Museum (Natural History), now the Natural History Museum, were always sure of her full attention. Her influence on the development of taxonomic ichthyology during the last 60 years, and on maintaining the excellence of research work stemming from the museum, was profound. Those who were fortunate enough to receive their early professional training under her exacting, but kindly, guidance will be especially grateful to Ethelwynn Trewavas.
Born in Penzance, Cornwall, in 1900, she was educated first at St Paul's infant school in that town, and then between 1909 and 1917 at the West Cornwall College. From 1917 until 1921 she was a student at Reading University (then Reading University College), where she obtained her BSc Honours degree and a Board of Education Certificate in teaching. It was during the latter part of her undergraduate studies that she undertook her first piece of research, on sea urchins, the results of which were published a year later in the Journal of the Marine Biological Association. It was not until 1925, and after four years as a science teacher in various schools, that she was able to start research, on a near full-time basis, when for some two years she was employed as a part-time demonstrator at King's College of Household & Social Sciences (later to become Queen Elizabeth College of London University).
Her researches there were principally on certain anatomical features in frogs and toads and resulted in an important paper, later published in the Philosophical Transactions of the Royal Society (1933).
During the time she was at King's College, Trewavas first met Dr C. Tate Regan, Director of the British Museum (Natural History), an event which, fortunately for ichthyology, had a marked influence on her subsequent career. Tate Regan, an outstanding ichthyologist, required a personal assistant, and impressed by Trewavas's enthusiasm and abilitiies, he arranged to employ her. She held this semi-official post until her transfer, in 1935, to the museum's permanent staff as an Assistant Keeper.
Infected by Regan's enthusiasm for research into African fishes, but equally intrigued by the deep-sea anglerfishes on which he worked, Trewavas collaborated with him on research into both groups. Her particular interests, however, soon centred on one family of freshwater fishes, the African members of the family Cichlidae. These parch-like fishes are represented in Africa by over a thousand species, many endemic to certain lakes and river systems. Although often superficially very similar in appearance, the various species have different feeding habits and ecological preferences, thus playing an important role in the bioeconomy of the lakes; many are also of economic importance.
Trewavas's fundamental researches on these fishes, and especially those of Lake Malawi, laid the foundations for the many later studies by ichthyologists, evolutionary biologists and fishery scientists. In particular, her detailed studies on one group of cichlids, the tilapias, and on the cichlids of Lake Malawi, will be permanent and practical memorials to her work. Her tilapia monograph (1981) is unlikely to be replaced for many decades and, like her earlier paper on the cichlids of Lake Malawi (1935), will enter the lists of ichthyological classics. The latter paper she intended to expand considerably once she had analysed the data and specimens she had collected during a visit to Lake Malawi in 1939. That visit, undertaken with Kate Picardo Bertram and HJH Borley, was at the behest of the Colonial Office who required a survey of the lake's fishes and fisheries. The volume of survey results was published in 1942, and until well after the Second World War remained the only document of its kind. It, together with her 1935 paper, were 'bibles' for all subsequent fishery research workers on the lake.
The outbreak of war prevented Trewavas from completing her proposed elaboration of the 1935 paper, and, of course, severely hindered her work in the museum. But, despite her involvement in the difficult task of evacuating specimens from London to the safety of caves near Tring, and the upheavals of wartime life, she managed to continue working and to publish several papers. However, it was not until 1989, 28 years after her official retirement, that her long-awaited monograph on Malawi cichlids was published. As was so typical of Trewavas's generosity, she gave the senior authorship of that book to her co-worker whom, because of her failing eyesight, she had invited to assist her in its preparation.
The immediate post-war years once again brought her into close involvement with the African lakes, in part through her help and advice to the numerous young scientists then working in Africa, and in part through her becoming, in 1945, a member of the Fishery Advisory Committee to the Secretary of State for the Colonies. That task she undertook for many years, with benefit both to her fellow committee members and, especially, to research workers in the field who all too often were struggling with the attitudes of uncomprehending local and home-based bureaucrats. Two years later, at the invitation of the Nigerian government, she joined their Fisheries Development Unit in the field for two months.
Her field studies continued for many years after her retirement, and included visits to Kenya, Tanzania, Malawi, Zambia, and the crater lakes of the Cameroons. All resulted in the museum's receiving the substantial collections of specimens on which several of her papers were based.
Besides her involvement with the Colonial Office Fisheries Advisory Committee and the training of Fishery officers in the Colonial Service, Trewavas served for several years on the council of the Freshwater Biological Association, as she did on those of the Systematics Association, and of the Institute of Biology. As a dedicated scientist whose research time was already deeply eroded by commitments to the museum, her colleagues and students, Trewavas had many misgivings about accepting the Deputy Keepership of Zoology offered to her by the museum's Trustees in 1958. Her loyalty to the museum, however, overcame those doubts, and she served in that capacity until she retired in 1961.
As a Deputy Keeper she showed to the full her concern for the problems of the museum and its staff, and in particular her sense of fair play and justice, all activities which added to the wear and tear of her life and reduced her research output. That setback was soon overcome, however, during her long 'retirement', during which she published several substantial papers, the monograph on the tilapiine fishes and that on the cichlids of Lake Malawi. Needless to say, she continued her close association with her professional colleagues and with international aquarist groups; all that despite increasing problems with her eyesight.
Ethelwynn Trewavas's outstanding contributions to ichthyology were recognised by the award of the Linnean Society of London's Linnean Medal (1968) and by her election as Fellow Honoris Causa in 1991; by election to Honorary Foreign Membership of the American Society of Ichthyologists and Herpetologists (1946); and by Stirling University which, in 1986, awarded her the degree of Doctor of Science (Honoris Causa).